Michael O'Brien



+1 416 617 0533


Bar Admissions:
Ontario, 2013


  • Arbitration & Mediation
  • Class Actions
  • Commercial Litigation
  • Dispute Resolution
  • Lobbying & Conflicts of Interest Investigation
  • Securities Litigation

Michael takes a practical and strategic approach to solving complex problems.

Michael O’Brien is a partner at Tyr LLP. Prior to joining Tyr LLP in October 2019, Michael carried on a general commercial and civil litigation practice at McCarthy Tétrault LLP.

Michael is a trusted advisor to publicly traded and privately held companies, public institutions, investors and high-profile individuals. He has experience assisting clients in a broad range of industries, in all manner of disputes, including civil, commercial, regulatory and class proceedings. An experienced advocate, he has represented clients as first and second chair at motions, hearings, trials and appeals before various courts and administrative tribunals in Ontario. Businesses and individuals also consult Michael on their obligations in the political sector, including ethical compliance, conflicts of interest and lobbying law.

In addition to his diverse trial practice, Michael was formerly the Vice-Chair of the American Bar Association's Business Law Section subcommittee on Class Actions. From 2014 - 2019 he contributed to and edited the Class Actions chapter in the ABA's annually updated Recent Developments in Business and Corporate Litigation.

  • Successfully obtained injunctive relief for a major financial institution to compel a software service provider to end the improper shut down of a vital software service in breach of the contract between the parties.
  • Assisted auditor in shareholder misrepresentation class action involving allegations of misrepresentations made in public disclosure documents.
  • Represented the master distributor in a chemical supply chain successfully prosecute a multi-million dollar claim for numerous breaches of a master distributor agreement. The dispute was resolved in favour of the master distributor in advance of private arbitration.
  • Representation of energy companies in various proceedings relating to wind power projects in Ontario.
  • Representation of an energy company, defending allegations of abuse of dominance made by the Commissioner in the Competition Tribunal.
  • Through an internal investigation for a major financial institution, ensured that key personnel were appropriately prepared for anticipated inquiries from various government committees and commissions.
  • Advise a variety of clients on obligations, risks and procedures associated with responding to various government commissioners.
  • Assisted large financial institution take prompt action to ensure the containment of stolen confidential data.
  • Successfully exonerated the target of an OSC investigation for insider trading following an investigation into the target’s trading patterns, publicly available information, and the cross-examination of the OSC’s investigator.
  • Successfully appealed a professional licensing body’s decision to deny Certificate of Registration to a professional, including obtaining the extraordinary order requiring the licensing body to issue the professional a Certificate of Registration.
  • Represented numerous professionals before their regulatory body, including at the investigative stage before their Discipline Committee, as well as on appeal from various administrative tribunals.


  • Co-Founder & Co-Chair, The Charter Project, a public awareness and education initiative regarding the Canadian Charter of Rights and Freedoms
  • Chair, Board of Directors, Camp Ekon, 2015 – 2019
  • Member, Board of Directors, Camp Ekon, 2013 – 2015


  • "Comparing Class Actions in Canada to those in the U.S." in Defending Class Actions in Canada: A Guide for Defendants, 5th Edition, published by LexisNexis in December 2019 (chapter co-author).
  • "Cross-Border & Multijurisdiction Class Actions—A Canadian Perspective" in the American Bar Association’s annually updated volume, Recent Developments in Business and Corporate Litigation (2014, 2015, 2017, 2018, 2019) (Co-author and Co-editor).
  • "Cross-Border & Multijurisdiction Class Actions—A Canadian Perspective" in Recent Developments in Business and Corporate Litigation: Class Action Law, 2016 Edition, published by the American Bar Association in July 2016 (Co-author and Co-editor).
  • "Multijurisdictional Issues" in Defending Class Actions: A Guide for Defendants, 4th Edition, published by LexisNexis in December 2015 (chapter co-author).


  • Since 2018, Michael has been a faculty advisor at the Ryerson LPP Trial Advocacy Training Workshop.
  • In 2020, Michael co-taught the Corporate Remedies class for the Professional LLM program at Osgoode Hall, York University.


  • The Advocates’ Society
  • Canadian Bar Association
  • Ontario Bar Association
  • American Bar Association
  • Vice-Chair, sub-committee on Class Actions, Business and Corporate Litigation Committee, Business Law Section (2016-2019)


  • University of Windsor, J.D., 2012
  • University of Waterloo, M.A., English, 2010
  • University of Waterloo, B.A.H., English Language and Literature, 2007